Hello thanswr1017

                                   SBG6700-AC or any of the Arris products we don't have any option to check the data usage on the modem interface so to monitor your data usage on daily basis or the way you like you need to use separate application for that and you can google or you need to check with your Internet service provider for those details.

You will need to login to your router's web interface (192.168.0.1), there is a tab named Basic if you click on it, it will display some other options click on DHCP and search for the client list section and there you will be able to see how many devices are connected, if you don't recognize a device you can block it if i'm not mistaken

But yeah keep in mind that Arris devices don't have the option to monitor data usage

I’ve ran into this issue before myself. Its a challenge to find whats causing the issues. 

I’ve been hit by a miner that was burning 100’s of gigs a day. And other times, I noticed a change when the streaming services auo-adjusted up to 4k from 1080p. 

How much data had you been using? 

How much are you using now? 

do you game/stream/etc? 

Thank you for your reply.  

How do I login to my router?  

Thanks in advance

You can find manuals here: https://arris.my.salesforce-sites.com/consumers/ConsumerProductDetail?p=a0ha000000NJohzAAD

They go over how to access it, settings, etc